System, method and computer program for timing interceptor missile warhead initiation

ABSTRACT

An interceptor missile comprising: a warhead; a processing unit; one or more sensors configured to obtain at least one reading enabling determination of a passing direction of the interceptor missile with respect to a target; wherein the processing unit is configured to: receive the reading from the sensors; determine a passing direction utilizing the reading; and obtain a required time T go  for initiating the warhead, utilizing the determined passing direction.

TECHNICAL FIELD

The disclosure relates to a system and method for timing interceptormissile warhead initiation.

BACKGROUND

When an interceptor missile is launched towards a target, the missile isset to initiate its warhead at a certain point-in-time T_(go). T_(go)can be calculated using various known techniques and methods. However,these techniques and methods do not consider a passing direction of thewarhead with respect to the target. There can be at least two passingdirection scenarios: (a) tail passing, in which the interceptor passesthe target at the aft (the interceptor missile's trajectory passes abovethe target), and (b) head passing, in which the interceptor passes thetarget at the nose (the interceptor missile's trajectory passes belowthe target). As detailed herein, considering the passing direction ofthe interceptor missile with respect to the target while determining theinitiation time of the interceptor's warhead (t_(go)) can increase thelethality of the interceptor missile and increase the likelihood ofdestroying the target.

There is thus a need in the art for a new system and method for timinginterceptor missile warhead initiation.

SUMMARY

In one aspect, in accordance with the disclosed subject matter there isprovided an interceptor missile comprising: a warhead; a processingunit; one or more sensors configured to obtain at least one readingenabling determination of a passing direction the interceptor missilewith respect to a target; wherein the processing unit is configured to:receive the reading from the sensors; determine a passing directionutilizing the readings; and obtain a required time T_(go) for initiatingthe warhead, utilizing the determined passing direction.

In some cases, the reading enables determination of a range and a rangerate of the interceptor missile with respect to the target and theprocessing unit is further configured to obtain the range and the rangerate from the readings and initiate the warhead when T_(go) issubstantially equal to, or smaller then, the range multiplied by therange rate and divided by a power of two of a closing velocity of theinterceptor with respect to the target.

In some cases, T_(go) is obtained utilizing target informationindicative of a target type.

In some cases, T_(go) is a default value when the target type isunknown.

In some cases, the initiation time is determined such that the number offragments of the interceptor expected to hit the target is optimal.

In some cases, the initiation time is determined such that the number offragments of the interceptor expected to hit a selected part of thetarget is optimal.

In some cases, the selected part is the front of the target or the rearof the target.

In some cases, the required time T_(go) in case the passing direction isindicative of a tail-passing scenario, wherein the interceptortrajectory passes above the target, is different than the required timeT_(go) in case the passing direction is indicative of a head-passingscenario, wherein the interceptor trajectory passes below the target.

In some cases, the sensors are proximity sensors.

In some cases, the proximity sensors are proximity fuses.

In some cases, the passing direction is determined also utilizinginformation relating to the location of the proximity sensors on theinterceptor missile, and information of the interceptor missile rollangle and attack angle.

In some cases, the warhead is omni-directional.

In another aspect, in accordance with the disclosed subject matter thereis provided an interceptor missile comprising a warhead and a processingunit, the processing unit configured to determine an initiation time ofthe warhead based on a passing direction, the passing direction beingindicative of a tail passing, wherein the interceptor trajectory passesabove the target, or a head passing, wherein the interceptor trajectorypasses below the target.

In another aspect, in accordance with the disclosed subject matter thereis provided an interceptor missile comprising a warhead and a processingunit, the processing unit is configured to: provide data representativeof at least two warhead initiation times, each corresponding to adistinct passing scenario associated with a passing direction; calculatean interception passing direction based on data received from one ormore sensors of the interceptor; initiate the warhead at an initiationtime substantially equal to the warhead initiation time corresponding tothe interception passing direction.

In another aspect, in accordance with the disclosed subject matter thereis provided a method for timing initiation of a warhead of aninterceptor missile, the method comprising: receiving, by a processingunit, readings from one or more sensors configured to obtain at leastone reading enabling determination of a passing direction of theinterceptor missile with respect to a target; determining a passingdirection utilizing the readings; and obtaining a required time T_(go)for initiating the warhead, utilizing the determined passing direction.

In some cases, the reading enables determination of a range and a rangerate of the interceptor missile with respect to the target and themethod further comprises obtaining the range and the range rate from thereadings and initiating the warhead when T_(go) is substantially equalto, or smaller then, the range multiplied by the range rate and dividedby a power of two of a closing velocity of the interceptor missile withrespect to the target.

In some cases, T_(go) is obtained utilizing target informationindicative of a target type.

In some cases, T_(go) is a default value when the target type isunknown.

In some cases, the initiation time is determined such that the number offragments of the interceptor expected to hit the target is optimal.

In some cases, the initiation time is determined such that the number offragments of the interceptor expected to hit a selected part of thetarget is optimal.

In some cases, the selected part is the front of the target or the rearof the target.

In some cases, the required time Tgo in case the passing direction isindicative of a tail-passing scenario, wherein the interceptortrajectory passes above the target, is different than the required timeTgo in case the passing direction is indicative of a head-passingscenario, wherein the interceptor trajectory passes below the target.

In some cases, the sensors are proximity sensors.

In some cases, the proximity sensors are proximity fuses.

In some cases, the passing direction is determined also utilizinginformation relating to the location of the proximity sensors on theinterceptor missile, and information of the interceptor missile rollangle and attack angle.

In some cases, the warhead is omni-directional.

In another aspect, in accordance with the disclosed subject matter thereis provided a method for timing initiation of a warhead of aninterceptor missile, the method comprising determining an initiationtime of the warhead based on a passing direction, the passing directionbeing indicative of a tail passing, wherein the interceptor trajectorypasses above the target, or a head passing, wherein the interceptortrajectory passes below the target.

In another aspect, in accordance with the disclosed subject matter thereis provided a method for timing initiation of a warhead of aninterceptor missile, the method comprising: providing datarepresentative of at least two warhead initiation times, eachcorresponding to a distinct passing scenario associated with a passingdirection; calculating, by a processing unit, an interception passingdirection based on data received from one or more sensors of theinterceptor; and initiating the warhead at an initiation timesubstantially equal to the warhead initiation time corresponding to theinterception passing direction.

In another aspect, in accordance with the disclosed subject matter thereis provided a computer program comprising computer program code meansfor performing the following steps when said program is run on acomputer: receiving readings from one or more sensors configured toobtain at least one reading enabling determination of a passingdirection of the interceptor missile with respect to a target;determining a passing direction utilizing the reading; and obtaining arequired time T_(go) for initiating the warhead, utilizing thedetermined passing direction.

In another aspect, in accordance with the disclosed subject matter thereis provided a computer program comprising computer program code meansfor performing the following steps when said program is run on acomputer: determining an initiation time of the warhead based on apassing direction, the passing direction being indicative of a tailpassing, wherein the interceptor trajectory passes above the target, ora head passing, wherein the interceptor trajectory passes below thetarget.

In another aspect, in accordance with the disclosed subject matter thereis provided a computer program comprising computer program code meansfor performing the following steps when said program is run on acomputer: providing data representative of at least two warheadinitiation times, each corresponding to a distinct passing scenarioassociated with a passing direction; calculating an interception passingdirection based on data received from one or more sensors of theinterceptor; and initiating the warhead at an initiation timesubstantially equal to the warhead initiation time corresponding to theinterception passing direction.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the subject matter and to see how it may becarried out in practice, examples will be described, with reference tothe accompanying drawings, in which:

FIG. 1 is an illustration of an exemplary interceptor missile, inaccordance with the presently disclosed subject matter;

FIG. 2 is a block diagram illustrating an example of an interceptormissile mission computer, in accordance with the presently disclosedsubject matter;

FIGS. 3a and 3b are illustrations of exemplary passing scenarios, inaccordance with the presently disclosed subject matter;

FIG. 4 is an illustration of the number of fragments expected to hit thetarget depending on the initiation time of the warhead in two exemplarypassing direction scenarios, in accordance with the presently disclosedsubject matter;

FIG. 5 is a flowchart illustrating an exemplary interception process, inaccordance with the presently disclosed subject matter; and

FIG. 6 is an illustration of the calculation of time to T₀, inaccordance with the presently disclosed subject matter.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the subjectmatter. However, it will be understood by those skilled in the art thatsome examples of the subject matter may be practiced with these specificdetails. In other instances, well known methods, procedures andcomponents have not been described in detail so as not to obscure thedescription.

As used herein, and unless explicitly stated otherwise, the term“memory” refers to any module for storing data for the short and/or longterm, locally and/or remotely. Examples of memory may includeinter-alia: any type of disk including floppy disk, hard disk, opticaldisk, CD-ROMs, magnetic-optical disk, magnetic tape, flash memory,random access memory (RAM), dynamic random access memory (DRAM), staticrandom access memory (SRAM), read-only memory (ROM), programmable readonly memory (PROM), electrically programmable read-only memory (EPROM),electrically erasable and programmable read-only memory (EEPROM),magnetic card, optical card, any other type of media suitable forstoring electronic instructions and capable of being coupled to a systembus, and/or a combination of any of the above.

Usage in the specification of the term “for example”, “such as”, “forinstance”, “e.g.”, “say”, “possibly”, “optionally” “one example”,“illustrated example”, “some examples”, “another example”, “otherexamples”, “some other examples”, “various examples”, “one instance”,“some instances”, “another instance”, “other instances”, “some otherinstances”, “various instances”, “one case”, “some cases”, “anothercase”, “other cases”, “some other cases”, “various cases”, or variantsthereof means that a particular described feature, structure orcharacteristic is included in at least one non-limiting example of thesubject matter, but not necessarily in all examples. The appearance ofthe same term does not necessarily refer to the same example.

The term “illustrated example” is used to direct the attention of thereader to one or more of the figures, but it should not be construed asnecessarily favoring any example over any other.

It should be appreciated that certain features, structures and/orcharacteristics disclosed herein, which are, for clarity, described inthe context of separate examples, may be provided in combination in asingle example. Conversely, various features, structures and/orcharacteristics disclosed herein, which are for brevity, described inthe context of a single example, may also be provided separately or inany suitable sub-combination.

Unless specifically stated otherwise, as apparent from the followingdiscussions, it is appreciated that throughout the specification,discussions utilizing terms such as “receiving”, “obtaining”,“determining”, “initiating”, “providing”, “calculating” or the like,refer to the action(s) and/or process(es) of any combination ofsoftware, hardware and/or firmware. For example, these terms may referin some cases to the action(s) and/or process(es) of a machine such as acomputer, that manipulates and/or transforms data into other data, thedata represented as physical, such as electronic quantities, and/or thedata representing physical objects.

Referring now to the Figures, FIG. 1 is an illustration of an exemplaryinterceptor missile, in accordance with the presently disclosed subjectmatter.

The Interceptor missile 100 in accordance with the presently disclosedsubject matter can be any interceptor missile having a warhead,including an air-to-air interceptor missile, a surface-to-airinterceptor missile, or any other type of interceptor missile having awarhead.

The interceptor missile 100 comprises a warhead 120, which, whenactivated, can result in fragments of the interceptor missile 100 beingsprayed in a certain direction (in case the warhead 120 is designed inthis manner) or in all directions (in case the warhead 120 isomni-directional).

In some cases, the interceptor missile 100 further comprises one or moresensors (and in more specific cases two or more sensors) configured toobtain one or more readings indicative of a spatial relativity betweenthe interceptor missile 100 and a target (not shown). The readings caninclude the range and the range rate between the interceptor missile anda target, which can be obtained from the readings (in some cases thereadings can include data enabling determination of the range and therange rate and in such cases the range and range rate can be determinedutilizing such data).

The readings obtained by the sensors can enable determination of apassing direction, as indicated herein. It is to be noted that in somecases the sensors can be external to the interceptor missile 100 (e.g.they can be located on external platforms, including airborne platforms,ground platforms, etc.).

The passing direction can be indicative of a passing-direction scenario,e.g. a tail-passing scenario, wherein the interceptor missile's 100trajectory passes above the target, or a head-passing scenario, whereinthe interceptor missile's 100 trajectory passes below the target. It isto be noted that in some cases additional and/or alternativepassing-direction scenarios can exist.

In one particular example, the sensor can be a proximity sensor (e.g. aproximity fuse), having at least two antennas—an upper antenna 150 and alower antenna 160. The antennas can be positioned in a manner thatenables determination of a passing direction of the interceptor missile100 with respect to a target (utilizing the information relating to thelocation of the proximity sensors on the interceptor missile, and theinterceptor missile roll angle). For example, the antennas can bepositioned on substantially opposite sides of the interceptor missile100—the upper antenna 150 substantially on the upper side of theinterceptor missile 100 and the lower antenna 160 substantially on thelower side of the interceptor missile 100. Such positioning of theantennas results in coverage of a first area by the upper antenna 150and a second area by the lower antenna 160. It is to be noted that insome cases, in order to determine which antenna is the lower antenna 160and which antenna is the upper antenna 150, information about theinterceptor missile's 100 roll angle is required and can be obtainedusing known methods and/or techniques.

In the case of utilizing a proximity sensor, determining which antennasensed the target (e.g. the lower antenna 160 or the upper antenna 150)can enable determination of the passing direction of the interceptormissile 100 with respect to the target, for example by determining whichantenna (e.g. the lower antenna 160 or the upper antenna 150)sensed/senses the target in the area covered thereby. In some cases, ifthe lower antenna 160 sensed the target, the interception scenario is atail passing scenario, whereas if the upper antenna 150 sensed thetarget, the interception scenario is a head passing scenario.

In some cases, if a certain antenna sensed the target during a certainpart of the interception process and another antenna sensed the targetduring another part of the interception process, the time of sensing canbe taken into account and a series of readings received from the sensorscan be utilized for determining the evolution of the interceptionscenario and the corresponding passing scenario.

It is to be noted that in the example provided above only two antennasare used, however a larger number of antennas can be used as well (e.g.distributed in a known manner on the interceptor missile 100). It is tobe further noted that other types of sensors can be used, such as aradar, an electro-optical sensor, etc., as long as the data acquired bythe sensors enables determination of a passing direction scenario(tail-passing or head-passing), and a range and a range rate between theinterceptor missile and a target. In addition, in some cases more thanone sensor and/or sensor type can be used for this purpose.

In accordance with the presently disclosed subject matter, the one ormore sensors are connected (e.g. via a wired or wireless connection) toa mission computer 110, as further detailed herein with respect to FIG.2, Attention to which is now drawn.

FIG. 2 is a block diagram illustrating an example of an interceptormissile mission computer, in accordance with the presently disclosedsubject matter.

In some cases, mission computer 110 can be connected to one or moresensors 240 in any manner that enables mission computer 110 (or anycomponent thereof) to receive at least one readings acquired by the oneor more sensors 240 including a range and a range rate (or data enablingdetermination thereof) between the interceptor missile and a target.

Mission computer 110 further comprises a processing unit 200. Processingunit 200 comprises, or is otherwise associated with, at least oneprocessor (e.g. digital signal processor (DSP), microcontroller, fieldprogrammable gate array (FPGA), application specific circuit (ASIC),etc.) configured to manage and control different components of missioncomputer 110 and carry out the relevant operations.

Processing unit 200 can comprise a passing direction determinationmodule 220 and an initiation time determination module 230. Processingunit can still further comprise, or be otherwise associated with, a datarepository 210.

According to some embodiments of the presently disclosed subject matter,passing direction determination module 220 can be configured to obtainreadings acquired by the one or more sensors 240 for determining apassing direction. The passing direction can be indicative of apassing-direction scenario, e.g. a tail-passing scenario, wherein theinterceptor missile's 100 trajectory passes above the target, or ahead-passing scenario, wherein the interceptor missile's 100 trajectorypasses below the target. It is to be noted that in some cases additionaland/or alternative passing-direction scenarios can exist.

In some cases, initiation time determination module 230 can beconfigured to determine the initiation time of the interceptor missile's100 warhead 120, as further detailed herein, inter alia with respect toFIGS. 5 and 6.

Data repository 210 can be configured to store, and enable retrieval of,data indicative of various warhead initiation times (T_(go)), dependingon one or more of: a target type, a passing direction, a selected partof the target to be hit, etc., as further detailed herein, inter aliawith respect to FIG. 5. Data repository can be part of the missioncomputer 110, or it can be otherwise operatively connected thereto.

Turning to FIGS. 3a and 3b , there are shown illustrations of exemplarypassing scenarios, in accordance with the presently disclosed subjectmatter.

In FIG. 3a , a head passing scenario is depicted. In such scenario, theinterceptor trajectory 310 of the interceptor missile 100 passes belowtarget 320. In order for the warhead fragments to hit the target 320 insuch head passing scenario, the warhead initiation should be timed to acertain point in time, Tgo 340, so that the fragments velocity vector330 will cause the fragments of the interceptor missile 100 to hit thetarget 320 in a successful manner (e.g. in a manner that will result indestruction of the target 320 or otherwise damaging the target so thatit is unable to achieve its mission). It can be appreciated that thefragments velocity vector 330 is derived of the interceptor velocitydirection (in the drawing it is aligned with the interceptor trajectory310) and the warhead fragments velocity vector 330 (e.g. a vectoraddition thereof). It can be further appreciated that most targets havea larger length then width so that the surface area of the target 320the warhead fragments are required to hit in a head passing scenario(where the fragments trajectory is substantially lateral to the target)is smaller than the surface area in a tail passing scenario (where thefragments trajectory is substantially perpendicular to the target, ascan be seen in FIG. 3b ). This results in head passing scenarios beingmore sensitive to variations in timing of the interceptor missile's 100warhead in comparison to tail passing scenarios as described withreference to FIG. 3 b.

In FIG. 3 b, a tail passing scenario is depicted. In such scenario, theinterceptor trajectory 310 of the interceptor missile 100 passes abovetarget 320. In order for the warhead fragments to hit the target 320 insuch tail passing scenario, the warhead initiation should be timed to acertain point in time, Tgo 340, so that the fragments velocity vector330 will cause the fragments of the interceptor missile 100 to hit thetarget 320 in a successful manner (e.g. in a manner that will result indestruction of the target 320 or otherwise damaging the target so thatit is unable to achieve its mission). It can be appreciated that thefragments velocity vector 330 is derived of the interceptor velocitydirection (in the drawing it is aligned with the interceptor trajectory310) and the warhead fragments velocity vector 330 (e.g. a vectoraddition thereof). It can be further appreciated that most targets havea larger length then width so that the surface area of the target 320the warhead fragments are required to hit in a tail passing scenario(where the fragments trajectory is substantially perpendicular to thetarget) is larger than the surface area in a head passing scenario(where the fragments trajectory is substantially lateral to the target,as can be seen in FIG. 3a ). This results in tail passing scenariosbeing less sensitive to variations in timing of the interceptormissile's 100 warhead in comparison to head passing scenarios asdescribed with reference to FIG. 3 a.

FIG. 4 is an illustration of the number of fragments expected to hit thetarget depending on the initiation time of the warhead, in two exemplarypassing direction scenarios, in accordance with the presently disclosedsubject matter.

As indicated herein, the initiation time of the interceptor missile's100 warhead (Tgo) has a direct effect on the number of fragmentsexpected to hit the target in each passing scenario. Looking at thegraph shown in FIG. 4, the vertical axis represents the number offragments expected to hit the target (# fragments 404) and thehorizontal axis represents the initiation time of the interceptormissile's 100 warhead (Tgo 402). Two curves appear in the graph, onerepresenting an exemplary head passing scenario 410 and the otherrepresenting an exemplary tail passing scenario 420. The peak of eachcurve represents the maximal number of fragments expected to hit thetarget at the respective passing scenario and each such peak isassociated with a corresponding Tgo.

Looking at the curve that represents an exemplary head passing scenario410, it can be appreciated that it has a peak at the point marked“optimal initiation time head passing 430” (i.e. when Tgo equals optimalinitiation time head passing 430). Looking at the curve that representsan exemplary tail passing scenario 420, it can be appreciated that ithas a peak at the point marked “optimal initiation time tail passing440” (i.e. when Tgo equals optimal initiation time tail passing 440). Itcan be appreciated that optimal initiation time head passing 430 isdifferent than optimal initiation time tail passing 440.

Assuming that a certain minimal number of fragments are required to hitthe target (e.g. for destroying it or otherwise damaging it so that itis unable to 30 achieve its mission) is provided, e.g. as indicated bymin # fragments 450 in the illustrated graph, it can be appreciated thatat least in some cases (as shown in the illustrated example) initiatingthe interceptor missile's 100 warhead 120 at optimal initiation timetail passing 440 when in fact the passing scenario is head passing, canresult in a lower number of fragments (e.g. in comparison to the minimalnumber of fragments 450) will hit the target, thus potentially failingthe interception. In a similar manner, initiating the interceptormissile's 100 warhead 120 at optimal initiation time head passing 430when in fact the passing scenario is tail passing, can result in a lowernumber of fragments (e.g. in comparison to the minimal number offragments 450) hitting the target, thus potentially failing theinterception.

It can also be appreciated when looking at the illustrated example andas indicated above, that the time sensitivity for initiating the warhead102 in a tail passing scenario is lower than the time sensitivity forinitiating the warhead in a head passing scenario. Looking at the graph,it can be appreciated that the time range for initiating the warhead 102for a successful interception at a tail passing scenario (marked tailpassing range 460) is much wider than the time range for initiating thewarhead 102 for a successful interception at a head passing scenario(marked head passing range 470), and thus less sensitive to the timingof the warhead 102 initiation.

It can be thus appreciated that identifying a passing scenario andtaking it into consideration when calculating the initiation time of aninterceptor missile's 100 warhead 102 is advantageous.

It is to be noted that the illustrated graph is merely an example and itis by no means limiting. For example, in some cases any one of thecurves may be different than shown in the illustration. In some cases,the tail passing range 460 and the head passing range 470 can partiallyor completely overlap. In some cases the minimal number of fragments 450can be lower or higher. In some cases, the curves can overlap (e.g. whenthe target has a cubic shape). Other reasons for variations in the graphand/or the curves and/or the optimal initiation times and/or the minimalnumber of fragments and/or the head/tail passing ranges, etc., mayexist.

Having described the relevancy of the passing scenario determination forthe interception process, attention is drawn to FIG. 5 is a flowchartillustrating an exemplary interception process, in accordance with thepresently disclosed subject matter.

According to certain embodiments of the presently disclosed subjectmatter, processing unit 200 can be configured to perform an interceptionprocess 500 (e.g. utilizing passing direction determination module 220and/or initiation time determination module 230).

For this purpose, processing unit 200 can be configured to receive atleast one reading of a range and a range rate (or reading/s enablingdetermination thereof) between the interceptor missile and a target(block 510). In some cases, the readings received in block 510 areobtained by the spatial relativity sensor/s 240. As indicated herein,the spatial relativity sensor/s 240 can be proximity sensors (e.g.proximity fuse/s).

Although reference is made to proximity sensors, it is to be noted thatany other sensor that can obtain data that enables determination ofrange and a range rate between the interceptor missile and a target canbe used, mutatis mutandis. For example, light sensing diodes or laserscan be utilized as sensors for obtaining the range and the range rate ordata enabling determination thereof. It is to be noted that in somecases, there may be a need of at least two sequential readings from thesensors as some sensors cannot obtain data including the range and therange rate in a single reading.

It is to be further noted that in some cases the range and a range rate(or data enabling determination thereof) between the interceptor missileand a target can be obtained by sensors external to the interceptormissile 100. For example, data obtained by a radar system that ismonitoring the interception can be used (e.g. a ground radar system oran airborne radar system, for example carried by an airplane that can belocated nearby an estimated interception location, etc.).

In some cases, the processing unit 200 can utilize the readings obtainedin block 510 for obtaining the range of the interceptor missile 100 tothe target (its distance therefrom) and the range rate of theinterceptor missile with respect to the target (block 520). In case thereadings do not contain such range and range rate, but data that enablesdetermination thereof, processing unit 200 can be configured todetermine the range and the range rate utilizing the readings.

Processing unit 200 can be further configured to determine a passingdirection of the interceptor missile 100 with respect to the target(block 530). In some cases, the passing direction can be determineddirectly utilizing the readings from the sensors. For example, it can bedetermined that if the lower antenna sensed the target, the interceptionscenario is a tail passing scenario, whereas if the upper antenna sensedthe target, the interception scenario is a head passing scenario.

Based on the passing direction, the processing unit 200 can beconfigured to obtain a required initiation time for initiating thewarhead (block 540). In some cases, the initiation time is relative toT₀ which is the time in which the distance between the interceptormissile 100 and the target is minimal (the minimal distance between theinterceptor missile 100 and the target is also referred to herein asMiss Distance, or MD). The determination of the time to T₀ (how longwill it take the interceptor missile 100 and the target to get to MD) isdetailed herein with reference to FIG. 6).

Assuming for example that for a tail passing scenario the initiationtime is 10 milliseconds, this can imply that the warhead initiationshould occur 10 milliseconds before T₀.

It is to be noted that the initiation time can be pre-determined (e.g.based on a-priori knowledge and/or experiments and/or estimates, etc.)and stored for example on data repository 210. It is to be further notedthat the initiation time can in some cases depend on one or morevariables such as: target information (e.g. a target type and/orinformation indicative thereof, a target shape and/or informationindicative thereof, etc.), a passing direction, a selected part of thetarget to be hit, etc. Thus, for example, assuming that the initiationtime depends on a passing direction, a target type, and a selected partof the target to hit, having knowledge of the passing direction in aspecific interception process, a specific target type to be interceptedduring the interception process, a specific part of the specific targetto be intercepted during the interception process, can enable retrievalof the corresponding initiation time from data repository 210.

Processing unit 200 can be further configured to initiate the warheadwhen the time to T₀ is equal (or substantially equal, e.g. within acertain range, e.g. several milliseconds/microseconds, etc.) to theinitiation time (which, as indicated above, is relative to the time theMD is minimal) (block 550). For this purpose, in some cases, theprocessing unit 200 can be configured to monitor the time to T₀, andcompare this time with the initiation time.

It is to be noted that in some cases the initiation time (T_(go)) incase the passing direction is indicative of a tail-passing scenario,wherein the interceptor trajectory passes above the target, can bedifferent than the initiation time (T_(go)) in case the passingdirection is indicative of a head-passing scenario, wherein theinterceptor trajectory passes below the target.

It is to be further noted that in some cases the initiation time isdetermined such that the number of fragments of the interceptor expectedto hit the target, or as selected part thereof (e.g. the front of thetarget or the rear of the target), is optimal.

It is to be still further noted that the interception process 500 isassumed to occur in a stage where neither the interceptor missile, northe target, accelerate. In case either one (or both) accelerates, theacceleration needs to be calculated as well and taken into account inthe determination of the passing scenario and in the determination ofthe initiation time of the warhead 102. In addition, the interceptionprocess 500 is assumed to occur when the target does not maneuver,however in cases the target does maneuver, such maneuvering can also betaken into account in the determination of the passing scenario and inthe determination of the initiation time of the warhead 102. Inaddition, the interception process 500 is assumed to occur when thetarget has no attack angle or a constant attack angle lower than acertain threshold (e.g. 30/20/10/5 degrees, etc.), however in cases thetarget's angle of attack is not constant, or not lower than thethreshold, the actual angle of attack of the target can also be takeninto account in the determination of the passing scenario and in thedetermination of the initiation time of the warhead 102.

It is to be further noted that all or part of the processes describedwith reference to blocks 510 to 550 can optionally be performed by acombination of one or more processing units external to the interceptormissile 100 (e.g. a processing unit of a ground station, an airplanethat launched the interceptor missile 100, a satellite, etc.).

It is to be still further noted that in some cases, fewer, more and/ordifferent blocks than those shown in FIG. 5, may be executed and notnecessarily in the order prescribed in FIG. 5. In some cases, one ormore of the blocks illustrated in FIG. 5 may be executed in a differentorder and/or one or more groups of blocks may be executedsimultaneously.

Turning to FIG. 6, there is shown an illustration of the calculation oftime to T₀, in accordance with the presently disclosed subject matter.

The time to T₀ (the time until the interceptor missile 100 and thetarget arrive at the minimal distance there between) can be calculatedusing a Pythagoras equation on a right triangle as depicted in thefigure. The first edge is the Miss Distance 620 itself (i.e. the minimalexpected distance between the interceptor missile and the targetassuming the interceptor missile warhead will not be initiated), whichis a constant number. The hypotenuse is the range between theinterceptor missile 100 and the target (marked R 610 in the figure). Thethird edge is the distance of the interceptor missile from the point atwhich it will be at the minimal distance from the target (markedVc(t-T₀) 630), and it is calculated by multiplying the closing velocity(Vc) between the interceptor missile and the target (i.e. the differencebetween the velocity of the interceptor missile and the target) with thetime that it will take the interceptor missile 100 and the target toarrive at the minimal distance there between (time to T₀ or t-T₀, whichis the purpose of the calculation).

It can be appreciated that the Pythagorean Theorem can be applied on theright triangle, and therefore:

(Vc(t−T ₀))² +MD ² =R ²   Formula 1

In order to find t-T₀, we can calculate a derivative of formula 1 withrespect to the time, and therefore:

(2Vc(t−T ₀))*Vc+0=2R*Rdot

Where Vc is the closing velocity between the interceptor missile and thetarget, R is the range between the interceptor missile and the target,and Rdot is the range rate (Rdot) between the interceptor missile andthe target. As Vc, R and Rdot are known, as detailed herein, inter aliawith respect to Fig, 5, t-T₀ can be calculated accordingly:

${t - {T\; 0}} = \frac{R*{Rdot}}{{Vc}^{2}}$

It will be understood that the subject matter contemplates that a systemor part of a system disclosed herein may be for example, a computer.Likewise, the subject matter contemplates, for example, a computerprogram being readable by a computer for executing a method or part of amethod disclosed herein. Further contemplated by the subject matter, forexample, is a computer readable memory tangibly embodying program codereadable by the computer for executing a method or part of a methoddisclosed herein.

The term “computer” should be expansively construed to cover anyelectronic system which includes at least some hardware and has dataprocessing capabilities, even if not labeled as such. For example, acomputer may be in some cases be capable of manipulating and/ortransforming data represented as physical, such as electronicquantities, within the registers and/or memories of the computer intoother data similarly represented as physical quantities within theregisters, memories, and/or other such information storage, transmissionand/or display elements of the computer.

While examples of the subject matter have been shown and described, thesubject matter is not thus limited. Numerous modifications, changes andimprovements within the scope of the subject matter will now occur tothe reader.

1. An interceptor missile comprising: a warhead; a processing unit; one or more sensors configured to obtain at least one reading enabling determination of a passing direction of the interceptor missile with respect to a target; wherein the processing unit is configured to: receive the reading from the sensors; determine a passing direction utilizing the reading; and obtain a required time T_(go) for initiating the warhead, utilizing the determined passing direction.
 2. The interceptor missile of claim 1 wherein the reading enables determination of a range and a range rate of the interceptor missile with respect to the target and wherein the processing unit is further configured to obtain the range and the range rate from the readings and initiate the warhead when T_(go) is substantially equal to, or smaller then, the range multiplied by the range rate and divided by a power of two of a closing velocity of the interceptor.
 3. The interceptor missile of claim 2 wherein T_(go) is obtained utilizing target information indicative of a target type.
 4. The interceptor missile of claim 2 wherein T_(go) is a default value when the target type is unknown.
 5. The interceptor missile of claim 1 wherein the initiation time is determined such that the number of fragments of the interceptor expected to hit the target is optimal.
 6. The interceptor missile of claim 1 wherein the initiation time is determined such that the number of fragments of the interceptor expected to hit a selected part of the target is optimal.
 7. The interceptor missile of claim 6 wherein the selected part is the front of the target or the rear of the target.
 8. The interceptor missile of claim 1 wherein the required time T_(go) in case the passing direction is indicative of a tail-passing scenario, wherein the interceptor trajectory passes above the target, is different than the required time T_(go) in case the passing direction is indicative of a head-passing scenario, wherein the interceptor trajectory passes below the target.
 9. The interceptor missile of claim 1 wherein the sensors are proximity sensors.
 10. The interceptor of claim 9 wherein the proximity sensors are proximity fuses.
 11. The interceptor missile of claim 9 wherein the passing direction is determined also utilizing information relating to the location of the proximity sensors on the interceptor missile, and information of the interceptor missile roll angle and attack angle.
 12. The interceptor missile of claim 1 wherein the warhead is omni-directional.
 13. An interceptor missile comprising a warhead and a processing unit, the processing unit configured to determine an initiation time of the warhead based on a passing direction, the passing direction being indicative of a tail passing, wherein the interceptor trajectory passes above the target, or a head passing, wherein the interceptor trajectory passes below the target.
 14. An interceptor missile comprising a warhead and a processing unit, the processing unit is configured to: provide data representative of at least two warhead initiation times, each corresponding to a distinct passing scenario associated with a passing direction; calculate an interception passing direction based on data received from one or more sensors of the interceptor; initiate the warhead at an initiation time substantially equal to the warhead initiation time corresponding to the interception passing direction.
 15. A method for timing initiation of a warhead of an interceptor missile, the method comprising: receiving, by a processing unit, readings from one or more sensors configured to obtain at least one reading enabling determination of a passing direction of the interceptor missile with respect to a target; determining a passing direction utilizing the readings; and obtaining a required time T_(go) for initiating the warhead, utilizing the determined passing direction.
 16. The method of claim 15 wherein the reading enables determination of a range and a range rate of the interceptor missile with respect to the target and wherein the method further comprising obtaining the range and the range rate from the readings and initiating the warhead when T_(go) is substantially equal to, or smaller then, the range multiplied by the range rate and divided by a power of two of a closing velocity of the interceptor missile with respect to the target.
 17. The method of claim 16 wherein T_(go) is obtained utilizing target information indicative of a target type.
 18. The method of claim 16 wherein T_(go) is a default value when the target type is unknown.
 19. The method of claim 15 wherein the initiation time is determined such that the number of fragments of the interceptor expected to hit the target is optimal.
 20. The method of claim 15 wherein the initiation time is determined such that the number of fragments of the interceptor expected to hit a selected part of the target is optimal.
 21. The method of claim 20 wherein the selected part is the front of the target or the rear of the target.
 22. The method of claim 15 wherein the required time T_(go) in case the passing direction is indicative of a tail-passing scenario, wherein the interceptor trajectory passes above the target, is different than the required time T_(go) in case the passing direction is indicative of a head-passing scenario, wherein the interceptor trajectory passes below the target.
 23. The method of claim 15 wherein the sensors are proximity sensors.
 24. The method of claim 23 wherein the proximity sensors are proximity fuses.
 25. The method of claim 23 wherein the passing direction is determined also utilizing information relating to the location of the proximity sensors on the interceptor missile, and information of the interceptor missile roll angle and attack angle.
 26. The method of claim 15 wherein the warhead is omni-directional.
 27. A method for timing initiation of a warhead of an interceptor missile, the method comprising determining an initiation time of the warhead based on a passing direction, the passing direction being indicative of a tail passing, wherein the interceptor trajectory passes above the target, or a head passing, wherein the interceptor trajectory passes below the target.
 28. A method for timing initiation of a warhead of an interceptor missile, the method comprising: providing data representative of at least two warhead initiation times, each corresponding to a distinct passing scenario associated with a passing direction; calculating, by a processing unit, an interception passing direction based on data received from one or more sensors of the interceptor; and initiating the warhead at an initiation time substantially equal to the warhead initiation time corresponding to the interception passing direction.
 29. A computer program comprising computer program code means for performing the following steps when said program is run on a computer: receiving readings from one or more sensors configured to obtain at least one reading enabling determination of a passing direction of the interceptor missile with respect to a target; determining a passing direction utilizing the readings; and obtaining a required time T_(go) for initiating the warhead, utilizing the determined passing direction.
 30. A computer program comprising computer program code means for performing the following steps when said program is run on a computer: determining an initiation time of the warhead based on a passing direction, the passing direction being indicative of a tail passing, wherein the interceptor trajectory passes above the target, or a head passing, wherein the interceptor trajectory passes below the target.
 31. A computer program comprising computer program code means for performing the following steps when said program is run on a computer: providing data representative of at least two warhead initiation times, each corresponding to a distinct passing scenario associated with a passing direction; calculating an interception passing direction based on data received from one or more sensors of the interceptor; and initiating the warhead at an initiation time substantially equal to the warhead initiation time corresponding to the interception passing direction. 